Dairy goats were fed a total mixed ration with or without the inclusion of castor oil [40 g/kg of dry matter (DM)] to study the metabolism of ricinoleic acid (12-OH,cis-9-18:1). Ten goats, at 39.7 ± 4.0 d in milk, were individually penned and allocated at random to the 2 experimental diets. Goats were manually milked twice a day. Milk fatty acids (FA) were analyzed as methyl esters and hydroxyl groups were derivatized in trimethylsilyl ethers. Apart from ricinoleic acid, 6 FA were only detected in the milk of the castor oil group. Ricinoleic acid composed 0.3% of total FA in milk of the castor oil group, whereas the hydroxy-FA (8-OH-14:0, 10-OH-16:0, and 12-OH-18:0) and oxo-FA (8-oxo-14:0, 10-oxo-16:0, and 12-oxo-18:0) reached 7.5% of total FA in milk. We anticipate that these FA were derived from the metabolism of ricinoleic acid, although it was not clear if they were produced in the rumen or in the tissues. To confirm that, we conducted in vitro batch incubations repeated for 3 consecutive weeks with castor oil (40 g/kg of DM) and strained rumen fluid from 2 fistulated sheep. To examine the products formed over time, incubation tubes were stopped at 0, 6, 12, 24, 48, and 72 h. The results of the in vitro experiment showed that ricinoleic acid was metabolized in the rumen at a slow rate and the main products formed were 12-OH-18:0 and 12-oxo-18:0, by hydrogenation of the cis-9 double bond, followed by oxidation of the hydroxyl group, respectively. Our results suggest that the 12-OH-18:0 and 12-oxo-18:0 escape rumen and are further metabolized through partial β-oxidation in ruminant tissues. We propose that the 10-OH-16:0 and 8-OH-14:0 found in goat milk of the castor oil group are successive products of the β-oxidation of 12-OH-18:0, and the 10-oxo-16:0 and 8-oxo-14:0 are successive products of the 12-oxo-18:0 in tissues. Overall, our results indicate that ricinoleic acid is extensively metabolized in the rumen and tissues, producing mainly oxo- and hydroxy-FA that are further excreted in milk.

The aim of this study was to evaluate the effects of the inclusion of the cactus Opuntia stricta (Haw.) in sheep diets on the feed intake, digestibility, fermentation, and physicochemical characteristics of the ruminal digesta. Five sheep cannulated in the rumen (61.5±9.5 kg body weight) were assigned in a Latin square design (5×5), with five diets and five experimental periods of 21 days each. The first 14 days were the adaptation period, and data were collected over the following [...] ABSTRACT The aim of this study was to evaluate the effects of the inclusion of the cactus Opuntia stricta (Haw.) in sheep diets on the feed intake, digestibility, fermentation, and physicochemical characteristics of the ruminal digesta. Five sheep cannulated in the rumen (61.5±9.5 kg body weight) were assigned in a Latin square design (5×5), with five diets and five experimental periods of 21 days each. The first 14 days were the adaptation period, and data were collected over the following

The aim of this study was to compare the gas production profiles and nutrient degradability of two diets using automatic and semiautomatic in vitro gas production techniques. A randomized block design in a 2 × 2 factorial arrangement was adopted, with two diets comprising different proportions of nonfiber carbohydrates (NFCs) (low-NFC vs. high-NFC diets), two gas production measurement techniques (automatic vs. semiautomatic) and four replicates. The blocks represent three in vitro runs. Gas production from the fermentation of fiber carbohydrates (Vf2) was 22% higher when measured with the automatic technique than with the semiautomatic technique. The Vt of the low-NFC diet differed between techniques and was 22.9% higher using the automatic technique. A highly positive correlation (r = 0.96) was observed between the techniques, with a high coefficient of determination between the techniques (R² = 0.93). There was greater degradability of dry matter (DMD) and organic matter (OMD) with the automatic technique. In both diets, the degradability of crude protein (CPD) was greater with the semiautomatic technique (p < 0.0001). The high-NFC diet resulted in a lower pH and lower NH₃-N in the incubation medium than in that of the low-NFC diet, whereas the degradability of DM, OM and CP increased. The automatic and semi-automatic techniques similarly estimated the kinetic parameters and the profiles of total gas production, demonstrating the potential of both techniques for assessing the nutritional value of diets with different proportions of NFCs.

This study aimed to evaluate the effect of the inclusion of spineless cactus (Opuntia stricta Haw) in the diet of sheep on the balance of macrominerals, renal function, and blood metabolites. Five sheep cannulated in the rumen (61.5±9.5kg body weight) were used in a 5 × 5 Latin square composed of five diets and five experimental periods. The experimental period lasted 105 days, with five periods of 21 days each. Four diets containing levels of spineless cactus (121, 245, 371, and 500g/kg of dry matter (DM)), and a control diet were evaluated. Samples of the ingredients, orts, feces, urine, and blood were collected. Spineless cactus inclusion in sheep diets increased the DM intake, ash, oxalate, and all macrominerals intake (P < 0.05), but did not affect the urinary and fecal excretion of P, as well as the concentration of P in the blood (P > 0.05). It is possible to verify that the inclusion of spineless cactus, up to the level of 500g/kg of DM in the sheep diets, does not appear to cause damage to the animal’s health. Its inclusion does not compromise kidney function or blood metabolites evaluated herein.

This study evaluated the influence of the propolis ethanolic extract (PEE) on gas production and in vitro degradability of sheep diets. Five experimental diets (treatments) were evaluated: without addition of PEE; 6 mL PEE; 12 mL PEE; 24 mL PEE and 36 mL PEE/kg concentrate. The experimental diet consisted of 50% elephant grass (Pennisetum purpureum) and 50% concentrate. There was a quadratic effect (P <0.05) for the volumes of total gas production (Vt), gases produced by the rapid degradation fractions (Vf1), and for in vitro degradability at 120 hours (Deg120), where the lowest values of Vt, Vf1 and Deg120, were found for the inclusion of 9.4 mL PEE/kg concentrate. Gas production by fermentation of the slow degradation fraction (Vf2) presented a mean of 25 mL/g DM (P <0.05). The colonization time of food particles (λ) significantly reduced (P<0.05) with increasing inclusion of PEE. Thus, it can be concluded that the PEE up to the inclusion of 9.4 mL/kg concentrate was efficient in inhibiting in vitro total gas production and from the fractions of rapid degradation by 9.9 and 15.3%, respectively, in addition to promoting a reduction of 5.3% in degradability after 120 h incubation in diets with a concentrate: forage ratio of 50:50. Thus, the inhibition in gas production was proportionally greater than the reduction of degradability.

The objective of this study was to assess the economics of the post-weaning phase and performance of Nellore calves born to dams that received protein concentrate supplementation during the final trimester of pregnancy. This research was organized into two phases: Phase I entailed a 90-day supplementation period for the dams in the last third of their pregnancy, and Phase II spanned from the birth of the calves to their weaning at 240 days. Twenty multiparous Nellore cows, subjected to fixed-time artificial insemination (FTAI), were divided into two groups: unsupplemented (US) and supplemented (SP), each comprising 10 animals. Statistical analysis was performed using an analysis of variance and the F-test with a significance level set at 0.05, within a completely randomized design. Among the parameters examined, only the total feed cost (US = BRL41.09 vs. SP = BRL112.22, P = 0.0001), effective operating cost (US = BRL872.51 vs. SP = BRL943.64, P = 0.0001), total operating cost (US = BRL925.51 vs. SP = BRL951.64, P = 0.0001), and total cost (US = BRL925.51 vs. SP = BRL996.64, P = 0.0001) were significantly affected by protein concentrate supplementation during the last third of pregnancy. Therefore, it can be concluded that while protein concentrate supplementation in the final stages of pregnancy does not influence the performance or morphological traits of calves, it does lead to increased feed and labor expenses. However, these increases do not negatively impact economic viability rates. Objetivou-se avaliar a economicidade da fase de cria e desempenho dos bezerros oriundos de vacas Nelore submetidas à suplementação concentrada proteica no terço final da gestação. O estudo foi dividido em duas fases. Fase I, 90 dias de suplementação das matrizes no terço final da gestação; Fase II, do nascimento ao desmame (240 dias) dos bezerros. Foram utilizadas 20 vacas Nelore multíparas a partir de inseminação artificial em tempo fixo (IATF), sendo divididas em dois grupos com 10 animais SS=Vacas não suplementação e CS=Vacas Suplementadas. Os dados foram interpretados estatisticamente por análise de variância e Teste F a 0,05 de probabilidade, em delineamento inteiramente casualizado. Entre as variáveis estudadas, apenas o custo total com alimentação (SS=R$41,09 e CS=R$112,22, P=0,0001), custo operacional efetivo (SS=R$872,51 e CS=R$943,64, P=0,0001), custo operacional total (SS=R$925,51 e CS=R$951,64, P=0,0001), custo total (SS=R$925,51 e CS=R$996,64, P=0,0001) foram influenciadas pela suplementação concentrada proteica no terço final da gestação. Desta forma, conclui-se que a suplementação concentrada proteica no final da gestação não influencia o desempenho e características morfológicas dos bezerros; eleva os custos com alimentação e mão de obra, porém, sem impactar negativamente os índices de viabilidade econômica.